Devices are known which measure the width of a vehicle tire on the ground as the vehicle passes along a road. In general, such devices comprise a pressure sensor embedded in the ground close beneath the zone on which the vehicle runs.
Such devices are not capable of accurately detecting tire widths and the spacing between tires of a vehicle as it passes.
The invention seeks to remedy this drawback. To this end, it provides a device for accurately detecting a dimension, and in particular a tread width on a path.